Archfiend of Ifnir

Flying
Whenever you cycle or discard another card, put a -1/-1 counter on each creature your opponents control.
Cycling {2} ({2}, Discard this card: Draw a card.)

Rakdos Guildgate

Rakdos Guildgate enters tapped.
{T}: Add {B} or {R}.

From Under the Floorboards

Madness {X}{B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
Create three tapped 2/2 black Zombie creature tokens and you gain 3 life. If this spell's madness cost was paid, instead create X of those tokens and you gain X life.

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Ancient Grudge

Destroy target artifact.
Flashback {G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Anthem of Rakdos

Whenever a creature you control attacks, it gets +2/+0 until end of turn and Anthem of Rakdos deals 1 damage to you.
Hellbent — As long as you have no cards in hand, if a source you control would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Incorrigible Youths

Haste (This creature can attack and {T} as soon as it comes under your control.)
Madness {2}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Asylum Visitor

At the beginning of each player's upkeep, if that player has no cards in hand, you draw a card and you lose 1 life.
Madness {1}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Davriel, Rogue Shadowmage

At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, Davriel, Rogue Shadowmage deals 2 damage to them.
−1: Target player discards a card.

Ancient of the Equinox

Autumnal Gloom

{B}: Mill a card.
Delirium — At the beginning of your end step, if there are four or more card types among cards in your graveyard, transform Autumnal Gloom.

Autumnal Gloom // Ancient of the Equinox

Tibalt, the Fiend-Blooded

+1: Draw a card, then discard a card at random.
−4: Tibalt, the Fiend-Blooded deals damage equal to the number of cards in target player's hand to that player.
−6: Gain control of all creatures until end of turn. Untap them. They gain haste until end of turn.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Arrogant Wurm

Trample
Madness {2}{G} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Dakmor Salvage

Dakmor Salvage enters tapped.
{T}: Add {B}.
Dredge 2 (If you would draw a card, you may mill two cards instead. If you do, return this card from your graveyard to your hand.)

Edge of Autumn

If you control four or fewer lands, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Cycling—Sacrifice a land. (Sacrifice a land, Discard this card: Draw a card.)

Call to the Netherworld

Return target black creature card from your graveyard to your hand.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Keldon Megaliths

Keldon Megaliths enters tapped.
{T}: Add {R}.
Hellbent — {1}{R}, {T}: Keldon Megaliths deals 1 damage to any target. Activate only if you have no cards in hand.

Necrogen Mists

At the beginning of each player's upkeep, that player discards a card.

Rakdos Augermage

First strike
{T}: Reveal your hand and discard a card of target opponent's choice. Then that player reveals their hand and discards a card of your choice. Activate only as a sorcery.

Dread Slag

Trample
Dread Slag gets -4/-4 for each card in your hand.

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Avatar of Discord

({B/R} can be paid with either {B} or {R}.)
Flying
When Avatar of Discord enters, sacrifice it unless you discard two cards.

Fiery Temper

Fiery Temper deals 3 damage to any target.
Madness {R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Psychotic Episode

Target player reveals their hand and the top card of their library. You choose a card revealed this way. That player puts the chosen card on the bottom of their library.
Madness {1}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Mountain

Bloodhall Priest

Whenever Bloodhall Priest enters or attacks, if you have no cards in hand, Bloodhall Priest deals 2 damage to any target.
Madness {1}{B}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Reckless Wurm

Trample
Madness {2}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Storrev, Devkarin Lich

Trample
Whenever Storrev, Devkarin Lich deals combat damage to a player or planeswalker, return to your hand target creature or planeswalker card in your graveyard that wasn't put there this combat.

Murderous Compulsion

Destroy target tapped creature.
Madness {1}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Awaken the Erstwhile

Each player discards all the cards in their hand, then creates that many 2/2 black Zombie creature tokens.

Stromkirk Occultist

Trample
Whenever Stromkirk Occultist deals combat damage to a player, exile the top card of your library. Until end of turn, you may play that card.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Rakdos Charm

Choose one —
• Exile target player's graveyard.
• Destroy target artifact.
• Each creature deals 1 damage to its controller.

Rakdos Pit Dragon

{R}{R}: Rakdos Pit Dragon gains flying until end of turn.
{R}: Rakdos Pit Dragon gets +1/+0 until end of turn.
Hellbent — Rakdos Pit Dragon has double strike as long as you have no cards in hand.

Swamp

Delirium Skeins

Grave Scrabbler

Madness {1}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
When Grave Scrabbler enters, if its madness cost was paid, you may return target creature card from a graveyard to its owner's hand.

Forest

Ramunap Excavator

Smoldering Marsh

({T}: Add {B} or {R}.)
Smoldering Marsh enters tapped unless you control two or more basic lands.

Dark Withering

Destroy target nonblack creature.
Madness {B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Werebear

{T}: Add {G}.
Threshold — Werebear gets +3/+3 as long as seven or more cards are in your graveyard.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Gruul Guildgate

Gruul Guildgate enters tapped.
{T}: Add {R} or {G}.

Lord Windgrace

+2: Discard a card, then draw a card. If a land card is discarded this way, draw an additional card.
−3: Return up to two target land cards from your graveyard to the battlefield.
−11: Destroy up to six target nonland permanents, then create six 2/2 green Cat Warrior creature tokens with forestwalk.
Lord Windgrace can be your commander.

Golgari Guildgate

Golgari Guildgate enters tapped.
{T}: Add {B} or {G}.

Jaya Ballard, Task Mage

{R}, {T}, Discard a card: Destroy target blue permanent.
{1}{R}, {T}, Discard a card: Jaya Ballard, Task Mage deals 3 damage to any target. A creature dealt damage this way can't be regenerated this turn.
{5}{R}{R}, {T}, Discard a card: Jaya Ballard deals 6 damage to each creature and each player.

Grow from the Ashes

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Search your library for a basic land card, put it onto the battlefield, then shuffle. If this spell was kicked, instead search your library for two basic land cards, put them onto the battlefield, then shuffle.

Big Game Hunter

When Big Game Hunter enters, destroy target creature with power 4 or greater. It can't be regenerated.
Madness {B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Ichor Slick

Target creature gets -3/-3 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)
Madness {3}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Rakdos Signet

Gibbering Descent

At the beginning of each player's upkeep, that player loses 1 life and discards a card.
Hellbent — Skip your upkeep step if you have no cards in hand.
Madness {2}{B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Azra Oddsmaker

At the beginning of combat on your turn, you may discard a card. If you do, choose a creature. Whenever that creature deals combat damage to a player this turn, you draw two cards.

Llanowar Wastes

{T}: Add {C}.
{T}: Add {B} or {G}. Llanowar Wastes deals 1 damage to you.

Jagged Poppet

Whenever Jagged Poppet is dealt damage, discard that many cards.
Hellbent — Whenever Jagged Poppet deals combat damage to a player, if you have no cards in hand, that player discards cards equal to the damage.

Abolisher of Bloodlines

Flying
When this creature transforms into Abolisher of Bloodlines, target opponent sacrifices three creatures of their choice.

Voldaren Pariah

Flying
Sacrifice three other creatures: Transform Voldaren Pariah.
Madness {B}{B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Voldaren Pariah // Abolisher of Bloodlines

Jund Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice Jund Panorama: Search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle.

Blood Scrivener

If you would draw a card while you have no cards in hand, instead you draw two cards and you lose 1 life.